DE10245104B4 - Projection arrangement and projection method - Google Patents

Abstract

projection arrangement with a light source (1), a light modulator (3), the one with Light of the light source (1) actable field from each other independently comprising controllable pixels (14), a projection optics (4) for projecting the pixels (14) onto a projection (8) and a control unit (5) for driving the pixels (14) of the Light modulator (3) and the projection optics (4), wherein the control unit (5) causes in a first of two temporally successive projection states each Pixels (14) according to data each one pixel of a given image driven and the pixels (14) with gaps between the pixels (14) are projected onto a projection surface (8) and that in the second the two projection states the pixels (14) in the spaces between them are projected, wherein in the second projection state, the pixels with Data are driven by the pixel data of the first Projection state are derived to be projected pixels, wherein the projection optics (4) contains a reduction optics (11) which when projecting the pixels (14) causes ...

Description

The The invention relates to a projection arrangement with a light source, a light modulator, which can be acted upon by light of the light source Field from each other independent comprising controllable pixels, a projection optics for projecting the pixels onto a projection screen and a control unit for driving the pixels of the light modulator.

at Such a projection arrangement is the difficulty that in the Projection of movies on the one hand a high single image resolution and the other a high refresh rate is necessary to the movie with the desired Project quality to be able to. These two criteria result in a large amount of data, even the current one existing computers is still causing significant problems. Therefore, will often a large data reduction, but a lot of effort requires and to a complex structure of the projection arrangement leads.

Farther are light modulators with a high resolution (ie a corresponding huge number of pixels) due to the complex production relatively expensive.

From the EP 0 712 243 A2 is a projection arrangement is known which has two light modulators, which are projected simultaneously offset from one another on a projection surface in order to increase the resolution.

outgoing It is the object of the present invention to provide a projection arrangement and to provide a projection method that provides higher resolution allow a smaller number of pixels.

According to the invention this is with a projection arrangement comprising a light source, a light modulator, the one with light from the light source acted field from each other independent controllable Contains pixels, a projection optics for projecting the pixels onto a projection screen and a control unit for driving the pixels of the light modulator as well the projection optics, wherein the control unit causes that in one of two temporally successive projection states each Pixels according to data each one pixel of a given image driven is and the pixels with spaces between the pixels are projected onto the projection surface and that in the second the two projection states the pixels in the spaces are projected, wherein in the second projection state, the pixels with Data are driven by the pixel data of the first Projection state are derived to be projected pixels, and wherein the projection optics include a reduction optics, the in the projection of the pixels causes each of the ratio of the Size of one projected pixels to the distance to the adjacent projected pixel less than the ratio the size of the pixel of the light modulator to the distance to the adjacent pixel of the light modulator.

With This projection arrangement will thus previously not exist Projected pixels of an image, these pixels other Information (eg brightness values, colors) can carry like the pixels of the picture. Thus, with the projection arrangement according to the invention a multiplication of the projected pixels and thus an increase in the resolution be achieved without the abzuspeichernde Data volume increased per image must become.

Further let yourself with such a reduction optics the necessary projection with gaps the image pixels easily realize, so that a small and easy projection arrangement to disposal can be made. Naturally the projection optics can be designed so that overall an enlarged picture the pixel field of the light modulator takes place.

When Projection of the pixels onto the projection surface is shown here on the projection screen Understood. This mapping is done so that the spaces between on the projection screen pictured pixels are present. If z. B. in the first projection state the picture is consistent colored area is, the projected image (the projected pixels) is no longer continuously, but has the spaces between them which are dark when the projection arrangement in a dark Room is operated. In the second projection state, the pixels become in the interstices projected. The projection is preferably performed so that the viewer just the overlay in both projection states projected pixels and thus the entire image can perceive.

The Representation of the image on the screen is typically done by looking at an observer from a defined distance. It is it is given physiologically that individual Pixels are only perceived when they are at a distance, which, when viewed, leads to an angle greater than 1 arc minute. It is therefore a further advantage of the invention by refinement the projected images or films by means of the second projection state projected pixels, which causes no pixel structure perceived more and thus the picture gives a soft impression, similar to the conventional film receives.

Especially the second projection state can have several individual states, in which successively at different points of the spaces between the Pixels are projected, with preference for the pixels in each individual state different data are derived. Thus, the gaps can also filled with several individual states, thereby further increasing the resolution can be achieved, so that too at a lower viewing distance, the pixel structure is not is more perceptible.

The Derivation of the data (in particular brightness values) for the projecting pixels in the second projection state can by means of the control unit and / or a separate computing unit (eg PC) become.

A very simple derivation consists of the pixel data of the to reuse the first projection state to be projected pixels so that Picture is at least twice projected slightly offset. This too leads to an apparent resolution improvement.

at a preferred embodiment of the projection arrangement according to the invention become the data for driving the pixels in the second projection state from the pixel data of the pixels to be projected, preferably the adjacent pixels to be projected, the first projection state calculated. An example of such a calculation is an interpolation or extrapolation, easily with the required speed are feasible, resulting in a high frame rate and thus a very good image representation (especially in movies) is achieved.

Further can in the projection arrangement according to the invention the reduction optics comprise a microlens array, with preferred for each Pixel a microlens is provided. Such a microlens array let yourself easy and inexpensive today so that the costs for the projection arrangement according to the invention barely rising.

Especially can in the projection arrangement according to the invention the reduction optics in a direction transverse to the light propagation direction of the coming from the light modulator and projected by the projection optics Be provided light movable. This can be done in the simplest way realizes an offset of the projected pixels in both projection states become. Preferably, the reduction optics in two different Directions (which are orthogonal to each other, for example) transverse to the light propagation direction movably provided, so that the Number of projected image pixels at least three times the number may be the pixel of the light modulator. The reduction optics For example, by means of appropriate actuators, by the Control unit to be moved.

Especially it is preferred if the projection arrangement according to the invention a the reduction optics downstream Strahlversatzeinheit comprises, the controlled by the control unit and in at least two different Positions can be brought, wherein in one of the two positions a desired Offset the projected pixels across the light propagation direction relative to the projected pixels when the beam offset unit in the other position, is effected. Such a blasting unit For example, by means of a rotatable, plane-parallel plate, the opposite the light propagation direction is inclined (an angle of not equal to 90 ° to the Lichtausbreitungsrichtung occupies) can be realized. alternative can also be provided a pivoting mirror, which in two Positions can be brought. In particular, a so-called galvanometer scanner be used. Furthermore, the Strahlversatzeinheit also two consecutively comprise connected plane-parallel plates or pivotable mirrors, so that more realized as two different positions or different offsets can be.

Of the Light modulator can be a reflective or transmissive light modulator The pixels are preferably arranged in rows or columns and switchable at least as a lighter or darker point are. If a pixel is switched to a bright pixel, it will he projected light projected onto the projection surface. From a pixel, which is switched as a dark pixel, either no light goes or the light emanating from it is not projected onto the screen. The light modulator can z. As a tilting mirror matrix or an LCD module be.

The Task is further by a projection method according to claim 6 solved.

With this method can be a high resolution despite a small amount of data per picture in particular realize can also cheaper Light modulators are used because with a smaller number of pixels a higher resolution can be achieved.

A preferred embodiment of the method according to the invention consists in that the data for a Pixel in the second step in each case from the pixel data of the derived adjacent pixels of the first step. Thereby let the data for quickly gain the pixel representation in the second step and that Picture presented makes an excellent impression.

Especially may be used to derive the data of the second step, a calculation be performed on the pixel data. So, for example an averaging (weighted or unweighted) done. Also other interpolation and extrapolation methods are possible.

Further can in the inventive method the first step to be performed before the second step. This leads to that Advantage that more time for the extraction of data for the pixel representation is present in the second step, since this already while the projection of the pixels in the first step is feasible.

A special embodiment of the method according to the invention is that the two Steps performed repeatedly become. This allows, for example, to project films. Of course you can too Still images are projected.

Further can in the method according to the invention in the second step two different and temporally successive following individual projections are performed, with the first of the two individual projections pixels in the spaces between the second Single projection and the first step and the second Single projection of pixels into the spaces of the first single projection and the first step are projected. This can be the resolution continue to increase, the image data for both Individual projections can be obtained in the specified manner and for both individual projections are preferably not the same. Of course you can second step, more than two individual projections are carried out, the together the spaces of the first step.

Especially the projection of the pixels into the spaces can be done so that for one Viewer, for the only overlay the projected pixel is perceptible, no spaces left are recognizable. For example, a slight local overlap the projected pixels of the two steps are generated.

The Derivation of the data for the projection of the pixels in the second step can be done during the Projection or before projection. If the data while derived from the projection, only a slightly larger amount of data be stored, since in this case z. B. in the projection from films only data for a few of the following images to be projected must be saved and not the data for all pictures of the movie.

The Invention will now be described by way of example with reference to the drawings in principle explained in more detail. It demonstrate:

1 a schematic representation of an embodiment of the projection arrangement according to the invention;

2 a schematic plan view of the light modulator of the projection array of 1 ;

3 a schematic plan view of the microlens array of 1 ;

4 the pixels of the light modulator projected onto the projection surface in a first position of the microlens array;

5 an enlarged view of a projected pixel of 4 ;

6 the pixels of the light modulator projected onto the projection surface in a second position of the microlens array;

7 the pixels of the light modulator projected onto the projection surface in a third position of the microlens array;

8th the pixels of the light modulator projected onto the projection surface in a fourth position of the microlens array, and

9 an enlarged view of a section of the projected pixels to explain the derivation of the data for the pixels to be projected.

In one embodiment, the projection arrangement according to the invention, as best of 1 it can be seen, a light source 1 (For example, a xenon lamp), one of the light source 1 downstream, about an axis D rotatable color wheel 2 and a light modulator downstream of this 3 which in the embodiment described herein comprises a tilting mirror array having a plurality of tilting mirrors (pixels) arranged in rows and columns, each of which can be switched to a first and a second tilted position.

Furthermore, the projection arrangement includes a projection optics 4 , a drive unit 5 and a light trap 6 ,

The light source 1 creates a light beam 7 that by the rotating color wheel 2 passes through and onto the light modulator 3 meets. The color wheel 2 is formed so that in each case depending on the rotational position of the color wheel 2 only light of different colors can pass through. So it can the light modulator 3 temporally one after another z. B. be illuminated with red, green and blue light. Depending on the tilt position of the individual tilting mirrors that of the one Individual tilt mirrors either reflected light onto a projection surface 8th (Light beam 9 ) or the light trap 6 (Light beam 10 ). The tilting position of the individual tilting mirrors is controlled by means of the control unit 5 set in accordance with predetermined image data, so that a red, green and blue partial image is projected in succession. We do this so quickly that the viewer perceives only the overlapping of the partial images as a multicolored image.

The projection optics 4 includes, as schematically in 1 shown is a microlens array 11 as well as a partial projection optics 12 , which is schematically drawn as a lens. The microlens array 11 can by means of an actuator 13 can be reciprocated in a direction indicated by the double arrow A and can continue to be moved back and forth by means of a second actuator (not shown) perpendicular to the plane of the drawing. The two actuators 13 be by means of the control unit 5 controlled. The effect of the movement of the microlens array will be described below.

In 2 is a schematic plan view of the light modulator 3 shown, with for simplicity only 64 tilting mirrors 14 (8 rows by 8 columns) are shown. In 3 is the microlens array 11 shown in a plan view. How one 3 are 64 microlenses 15 provided in the same way as the tilting mirror 14 (or pixels) are arranged in rows and columns, with each tilt mirror 14 one of the microlenses 15 assigned.

The microlens array 11 together with the projection part optics 12 leads when the microlens array 11 in the first position, to which in 4 shown projection image. The on the projection screen 8th illustrated tilting mirror (through the filled squares 16 in 4 indicated) are spaced from each other and have only a quarter of the size that they are in imaging without the microlens array 11 would have.

Thus, the ratio is the size of a projected pixel 16 (eg, its edge length) to the distance to the adjacent projected pixel is smaller than the corresponding ratio on the light modulator 3 , Overall, however, an enlargement of the pixel field of the light modulator 3 at the projection causes.

For clarification is in 5 a projected pixel 16 from 4 shown enlarged. Furthermore, the size of the projected pixel is still not filled square 17 plotted the pixel at projection without the microlens array 11 If you had the square 17 in four quadrants Q1, Q2, Q3, Q4 ( 5 ), the tilting mirrors become 14 only shown in the upper left quadrant Q1. Thus, between the projected pixels 16 , in the 4 There are gaps, namely the quadrants Q2, Q3 and Q4, respectively. The between each squares 17 plotted spaces are shown only to simplify the presentation and are not present in an actual projection.

The microlens array 14 can now by means of the actuators 13 be brought into a second position, which causes the tilting mirror 14 now in the upper right quadrant Q2 of the squares 17 be imaged 6 ). In a third position of the microlens array 11 become the tilting mirrors 14 in the lower right quadrant Q3 of the squares 17 pictured ( 7 ) and in a fourth position they become in the lower left quadrant Q4 of the squares 17 projected ( 8th ).

The described four positions of the microlens array are sequentially changed so fast that for the viewer, only the superposition of the four fields ( 4 and 6 to 7 ) is perceptible.

According to the invention, the projection arrangement projects a predetermined image which has as many pixels as the light modulator 3 tilting mirror 14 includes. In the (simplified) example described here, the image thus has 8 × 8 (64) pixels. To the projection brings the control unit 5 the microlens array 11 in its first position and controls the individual tilting mirror 14 corresponding to the pixels of the image, so that the individual pixels of the image in the first quadrant Q1 on the screen 8th be projected. In the example described, it is assumed that first the red partial image is projected, so that the tilting mirrors are driven in accordance with the brightness values of the red pixels.

After that brings the control unit 5 the microlens array in its second position (projection of the pixels in the second quadrant Q2, 6 ) and controls the tilting mirrors 14 according to data derived from the data of the 64 pixels. In the exemplary embodiment described here, an averaging of the data of neighboring pixels is carried out for this purpose. To illustrate this averaging are in 9 four projected pixels 18 . 19 . 20 . 21 during projection, when the microlens array 11 in his first position is shown. During the described second position of the microlens array 11 now become the pixels 22 and 23 projected, with their image information by averaging the image information of the pixels 18 and 19 respectively. 20 and 21 be won.

Thereafter, the control unit brings the microlens array 11 in his third position, so that now the Pixels are projected into the third quadrant Q3 (pixel 24 in 9 ). The data for the pixel 24 be by means of averaging the image information of the pixels 18 to 21 won.

After that, the microlens array 11 placed in its fourth position and the pixels are projected in the fourth quadrant Q4 (pixels 25 and 26 in 9 ). The image information for the pixels 25 . 26 are in turn by averaging the image information of the pixels 18 and 20 respectively. 19 and 21 won.

For pixels of the projection of the second to fourth position of the microlens array 11 which are not adjacent to two sides immediately from pixels of the projection in the first position of the microlens array (eg, pixel 27 in the whole right column in 6 ), further spaced pixels could be 28 . 29 ( 4 ) or their pixel data are used for averaging.

This procedure described is carried out successively for each of the three colors (red, green and blue). Of course, for each position of the microlens array 11 successively the color sub-images are projected, so that the microlens array 11 only after every full turn of the color wheel 2 must be placed in another position. The described method thus makes it possible to use a light modulator with a lower resolution (smaller number of pixels) without a significant reduction in quality. In particular, the amounts of data are thereby also significantly reduced (here by a factor of 4), which makes it possible in particular to render films more easily, since lower transmission capacities and storage media with a smaller storage capacity can be used.

Instead of the described averaging from the immediately adjacent Pixels can also more distant pixels in the averaging (preferred weighted). There are also other interpolations as well as other calculations (eg extrapolation) possible. Essential is that the Image information for three of the four positions of the microlens array from the image data be won or calculated for the projection during the first position were used.

Of course you can instead of the projection arrangement with a light modulator (so-called one-chip solution) as well a projection arrangement with z. B. three light modulators (for the colors red, green and blue) and a corresponding color divider unit are used, the are known in the art (so-called 3-chip solution).

In addition to the described quadrupling of the number of pixels, more derived pixels (pixels whose data are derived from the original pixel data) can also be generated per original pixel provided (pixels to which image data is present). Also, the quadratic patterns need not be generated by the various projection states. Any other pattern can be created as well. It is essential, in particular, for the viewer to be able to perceive an image without gaps (superposition of the individual states of projection ( 4 . 6 . 7 and 8th )).

Claims (11)

Projection arrangement with a light source ( 1 ), a light modulator ( 3 ), one with light from the light source ( 1 ) acted upon field of independently controllable pixels ( 14 ), a projection optics ( 4 ) for projecting the pixels ( 14 ) on a projection surface ( 8th ) and a control unit ( 5 ) for driving the pixels ( 14 ) of the light modulator ( 3 ) as well as the projection optics ( 4 ), the control unit ( 5 ) causes in a first of two temporally successive projection states each pixel ( 14 ) are driven according to data of a respective pixel of a given image and the pixels ( 14 ) with spaces between the pixels ( 14 ) on a projection surface ( 8th ) and that in the second of the two projection states the pixels ( 14 ) are projected into the intermediate spaces, wherein in the second projection state the pixels are driven by data derived from the pixel data of the pixels to be projected in the first projection state, the projection optics ( 4 ) a reduction optics ( 11 ) used in the projection of the pixels ( 14 ) causes each of the ratio of the size of a projected pixel to the distance to the adjacent projected pixel is smaller than the ratio of the size of the pixel of the light modulator to the distance to the adjacent pixel of the light modulator. Projection arrangement according to claim 1, in which the reduction optics comprise a microlens array ( 11 ), preferably for each pixel ( 14 ) a microlens ( 15 ) is provided. Projection arrangement according to Claim 1 or 2, in which the reduction optics ( 11 ) is movable in a direction transverse to the light propagation of the light coming from the light modulator and projected by the projection optics. Projection arrangement according to one of Claims 1 to 3, in which the projection optics ( 4 ) one of the reduction optics ( 11 ) downstream Strahlversatzeinheit comprises by means of the control unit ( 5 ) and in at least two positions can be brought, wherein in one of the two positions a ge desired offset of the projected pixels transversely to the light propagation direction of the light modulator ( 3 ) and by means of projection optics ( 4 ) projected light relative to the projected pixels when the beam offset unit is in the other position. Projection arrangement according to one of the above claims, in the data for driving the pixels in the second projection state from the pixel data of the adjacent pixels to be projected of the first projection state are calculated. Projection method in which a light modulator ( 3 ), which is a field of mutually independently controllable pixels ( 14 ), and the pixels are projected onto a screen with gaps between the pixels, the pixels being projected in two temporally successive steps so that the pixels of a second of the two steps are in the spaces of the first of the two steps In the first step, each pixel is driven according to data of a pixel of a given image and in the second step the pixels are driven by data derived from the pixel data of the pixels to be projected in the first step, thus projecting the pixels in that in each case the ratio of the size of a projected pixel to the distance to the adjacent projected pixel is smaller than the ratio of the size of the pixel in the field of the light modulator to the distance to the neighboring pixel in the field of the light modulator. The method of claim 6, wherein the data is for one pixel in the second step in each case from the pixel data of the adjacent thereto Pixels of the first step are derived. A method according to claim 6 or 7, wherein for the derivation the data for the pixels of the second step, a calculation, in particular a Interpolation of the pixel data, is performed. Method according to one of claims 6 to 8, wherein the first Step is performed before the second step. Method according to one of claims 6 to 9, wherein the two Steps are repeated. Method according to one of claims 6 to 10, wherein in the second Step two different individual projections are performed the pixels being one of the individual projections in the interstices of the projected to another individual projection.